Preferred Stock - Series B Convertible Preferred Stock (Details) $ / shares in Units, $ in Millions				12 Months Ended
	Sep. 17, 2014 shares	Aug. 12, 2013 USD ($) $ / shares	Mar. 09, 2012 $ / shares shares	Dec. 31, 2015 $ / shares shares
Series B Convertible Preferred Stock
Number of common shares sold | shares	15,784,313
Percentage of cumulative dividend rate				11.50%
Series B voting convertible preferred stock
Series B Convertible Preferred Stock
Period of closing of offering after which shares are convertible				5 years
Conversion price per share (in dollars per share) | $ / shares				$ 3.25
Conversion ratio, the number of shares of common stock received per share of convertible preferred stock				50
Reclassification of Series B preferred stock into shareholders' equity | $		$ 38.4
Series B-1 non-voting convertible preferred stock
Series B Convertible Preferred Stock
Number of common shares sold | shares			12,308
Offering price per share (in dollars per share) | $ / shares			$ 3,250
Period of closing of offering after which shares are convertible		5 years
Accumulated shares but undeclared dividends | shares				338,710
Redemption price (in dollars per share) | $ / shares		$ 7,430